Connections for coaxial cable means



Oct. 31, 1967 ,,w. ZIEGLER, JR

CONNECTIONS FOR COAXIAL CABLE MEANS 4 Sheets-$heet l INVENTOR. Mum; Z/[GMPTQ Q4: 7% f/M Filed Dec. 29, 1964 4 Sheets-$heet 2 iki i/b 15F a G. W. ZIEGLER, JR

CONNECTIONS FOR COAXIAL CABLE MEANS Oct. 31, 1967 Filed Dec. 29. 1964 GEORGE Mu Oct. 31, 1967 G. w'. ZIEGLER, JR 3,350,500

ONNECTIONS FOR COAXIAL CABLE MEANS Filed Dec. 29. 1964 4 Sheets-Sheet 3 I N VEN TOR.

0d. 31, 1967 G.W. ZIEGLER, JR I 3,

QNNECTIONS FOR COAXIAL CABLE MEANS Filed Dec. 29. 1964 4 Sheets-Sheet 4 INVENTOR. S00E65 Mum l 25645219.

United States Patent 3,350,500 CONNECTIONS FOR 'COAXIAL CABLE MEANS George William Ziegler, Jr., Carlisle, Pa, assignor to AMP Incorporated, Harrisburg, Pa. Filed Dec. 29, 1964, Ser. No. 421,903 13 Claims. c1. 174 s9) This invention relates to coaxial connectors and more particularly to a permanent splice therefor.

The transmission of high frequency and ultra highfrequency electromagnetic energy, such as in radar and television applications, is generally accomplished with coaxial cable. When it is desired to minimize leakage losses, coaxial cable utilizing a solid, as opposed to braided, outer conductor is useful. Such cable is usually classified as semi-rigid, as it can be bent over reasonably short radii. In connecting lengths of such cable, connectors are required which provide a physical connection joining the cable ends as well as providing electrical continuity between the respective outer conductors and inner conductors.

In some applications, a portion of the connector is applied to each cable end and the connector is provided with mating features so as to be disconnectable by, for example, unscrewing a collar. In many applications, the connection need not be broken and a permanent connection would be more desirable.

A perfect connection would be obtained if two cable ends could be abutted; the outer conductors made continuous with no change in inner or outer diameters; the dielectrics joined with no boundary layer between them; and the center conductors joined with no diameter change or change of conductivity. In the present state of development of cable terminations, such connections cannot be attained. The instant invention provides significant improvements over present cable terminations and closely approximates the ideal connector.

'One type of cable used in accordance with the present invention is coaxial shielded cable having a solid or hollow center conductor or one composed of strands. The dielectric material may be a solid, such as, Teflon, irradiated polyolefin, or polyethylene; a foamed plastic; one of the so-called air dielectrics comprising helically-wound membranes, layered structures, tubes or ribbons; a splined or star-shaped dielectric material composited with air to give a low effective dielectric constant; or a beaded structure. The outer conductor is generally solid aluminum or copper. When using a solid center conductor, a hole must be drilled therein. When using a stranded center conductor cable, it is usually found that a solid dielectric material is used, said material being under some compression and holding the lay of the strands so that, for example, the center strand of a seven-strand conductor may be drilled out plus a small amount of the surrounding six strands. Another type of cable is flexible coaxial cable having a solid, hollow or stranded center conductor, a dielectric material overlying the center conductor, a braided or spiralled outer conductor on the dielectric material and insulation surrounding the outer conductor. Other types of coaxial cables may, of course, be utilized in accordance with the principles of the present invention.

It is a principal object of this invention to provide a permanent splice for the above-mentioned cable, which splice may be applied onto the cable without the aid of expensive hydraulic, air, or electric tooling.

Another objectis to provide such a splice having a profile which is only slightly greater than the outside diameter of the cable.

A further object is to provide a permanent splice having a minimum impedance change from one cable to the other.

An additional object is to minimize the number of parts required by abutting the dielectrics and center conductors of the two cable ends.

Still further objects are to provide improved tensile strength, improved torque resistance and to allow the cable to bend adjacent to the joint.

Still additional objects are to provide resistance to corrosive environment, sealing to pressure or vacuum, and resistance to extremes of temperature, shock, acceleration and vibration.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are given for purposes of illustration and principles thereof and the manner of applying them in practical use so that they may modify them in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a perspective view of a completed splice on cable means;

FIGURE 2 is an exploded perspective view of one end of the cable means and parts of the splice assembly in cross section;

FIGURES 3-6 illustrate the various stages in applying a permanent splice to coaxial cable means;

FIGURE 6a is a partial cross-sectional view of an embodiment of the loading rings;

FIGURE 7 is an enlarged cross-sectional view of part of FIGURE 6 indicated by the number 7;

FIGURE 8 is a cross-sectional view of an alternative embodiment of the present invention; and

FIGURE 9 is a cross-sectional view of a further alternative embodiment of the present invention.

FIGURE 1 shows one end of coaxial cable means 1 permanently spliced to one end of a similarcoaxial cable means 2 via permanent splice assembly 3. Coaxial cable means 1, 2 comprises a center conductor 4, an outer metallic conductor 5, an insulation 6 disposed between conductors 4 and 5.

Each end of coaxial cable means 1 and 2 is placed in a tool (not shown) of the type disclosed in US. patent application, Serial No. 315,787, filed October 14, 1963, now US. Patent No. 3,270,392 which is assigned to the present assignee. If center conductor 4 is a solid conductor, then it is drilled to form a hole 7 therein. Conically-shaped loading rings 8 are placed on cable means 1 and 2 and are pushed along the cable means away from the ends thereof, as illustrated in FIGURE 3. The inside diameter of the smallest part of loading rings 8 is slightly larger than the outside diameter of cable means 1 and 2 while the inside diameter of the largest part of loading rings 8 will be discussed hereinafter. Loading rings 8 are made of a strong material, such as, beryllium copper or steel and are preferably plated with cadium or zinc. Rings 8 may also be aluminum clad; this will minimize corrosion electrolytic couples with outer conductor 5 if it is made of aluminum. If outer conductor 5 is made of copper, loading rings 8 may be copper-plated.

After loading rings 8 have been placed on cable means 1 and 2, the ends of the cable means are flared in an outward direction, as illustrated in FIGURE 3, by means of a flaring member 9, which is inserted in the ends of the cable means in an axial manner between the outer conduct'or 5 and insulation 6, as illustrated in FIGURE 3.

After holes 7 have been drilled in center conductors 4 and the ends of the cable means have been outwardly flared, a center contact member 10 is inserted into hole 7 of one of the cable means, as illustrated in FIGURE 4.

Center contact member has spring fingers 11 at each end thereof in order to resiliently hold center contact member 10 within holes 7. The ends of contact member 10 are preferably beveled so as to facilitate the insertion thereof within holes 7.

Center contact member 10 contains a centrally-located peripheral ring 12 large enough to bite into the center conductor material when the two center conductors are pushed together, yet this ring is small enough so that the center conductor outer diameter is not altered when the two center conductors are brought into abutting relationship, as illustrated in FIGURE 5. Center contact member 10 is preferably made of Phosphor bronze or beryllium copper and may be plated, preferably with gold or silver, to protect it from corrosion, to improve its electrical conductivity and to reduce contact resistance especially at ring 12. Peripheral ring 12 also serves to locate equal amounts of center contact member 10 within holes 7.

After center contact member 10 has been inserted into holes 7 of one of the cable means, an inner sleeve 13 is inserted into the flared ends of cable means 1 and 2 and the cable means are manually pushed together until center contact member 10 is seated in holes 7 of the other cable means, center conductors 4 and insulation 6 are in abutting relationship and the ends of the flared portions of the cable means are slightly disposed from one another because their length has been shortened due to the fact that they have been flared outwardly, as illustrated in FIGURE 5. The ends of inner sleeve 13 are preferably beveled so as to facilitate the insertion thereof within the flared ends of the cable means.

Inner sleeve 13 is made of a suitable strong metallic material, such as, beryllium copper and may be plated with silver or gold, both inside and out when used with a sealing ring 14 centrally located on the exterior surface of inner sleeve 13. Sealing ring 14 is preferably Isonel 31 varnish manufactured by Schenectady Varnish Company, Schenectady, New York; however, the outside of inner sleeve 13 may be coated in its central region with cadmium or with some other substance having a low corrosion potential to aluminum, such as zinc. Covering the exposed area will also prevent corrosion. Sealing rings 14 may be a piece or rubber, plastic or the like, which is squeezed between the ends of loading rings 8 when they are pushed together to overlie the flared ends of the cable means, as illustrated in FIGURE 6.

Now that the cable means are disposed in the manner set forth in FIGURE 5, loading rings 8 are axially moved along the cable means until the leading ends of the loading rings are in abutting relationship or slightly spaced from each other, as illustrated in FIGURE 6. The inside diameter of the largest part of loading rings 8 is such that when the loading rings are moved along the outwardly flared sections of the cable means, the outwardly flared sections of the cable means are bent inwardly in tight engagement with inner sleeve 13 and this causes the loading rings to be radially stretched thereby elastically storing great amounts of energy to maintain the connections in the region along the flared ends of the cable means.

. As can be discerned, the configuration of the loading rings conforms substantially to the configuration of the cable means from its unflared sections to its flared sections. Extensions 8' of loading rings 8 cause bending stresses to be applied away from the radially loaded area along inner sleeve 13, thereby providing a strong connection. A smooth transition occurs from the nonflaredsections of outer conductors 5 along the beveled ends of inner sleeve 13. The disposition of sealing ring 14 with respect to the ends of outer conductors 5 and loading rings 8 is illustrated in FIGURE 7.

Connections prepared in accordance with the teachings of the present invention have been subjected to axial stresses greater than those required to permanently deform the outer conductor of the cable means without impairment to the connection. The cable has been permanassgsoo nently deformed in torque without loosening the connection. A cable may be bent in a standard bending radius adjacent to either or both ends of the connection without detrimental effect thereto. Such connections have a voltage standing wave ratio less than that of the cable and present a negligible insertion loss. Connections fabricated according to the present invention have maintained eighty ('80) pounds gauge pressure for an extended period of time. The connections have withstood liquid nitrogen temperatures and, depending on choice of materials, these connections will perform at elevated temperatures.

FIGURE 8 illustrated an alternative embodiment of the present invention wherein a center contact member 10' similar in configuration to inner sleeve 13 surrounds a center conductor 4 of the cable means instead of drilling a hole therein. Otherwise, the other elements in FIG- URE 8 are similar to those set forth hereinabove.

FIGURE 9 illustrates a further embodiment of the present invention wherein coaxial cable means having a stranded center conductor 16, a braided outer conductor 17, a dielectric medium 18 disposed therebetween and insulation means 19 surrounding outer conductor 17. Center conductor 16 is drilled in both ends of the coaxial cable means in the manner set forth in embodiment of FIGURES 1-7 so that center contact member 10 can be inserted therein. Insulation means 19 is stripped back from the ends of the cable means, as illustrated in FIG- URE 9. Loading rings '8" are disposed on each cable means and inner sleeve 13 is inserted between outer conductor 17 and dielectric medium 18 of one of the cable means'after center contact member 10" is inserted in the center conductor thereof. Then, inner sleeve 13 is inserted between outer conductor 17 and dielectric medium 18 of the other cable means until the ends of the center conductors and the dielectric mediums are in abutting relationship. Clamping rings 20 are then disposed on the exterior surfaces of outer conductors 17 and loading rings 8 are pushed thereover in abutting or almost abutting relationship. Thus, the connection of coaxial cable means of the type disclosed in FIGURE 9 has all of the attributes of the connections illustrated in FIGURES 1-8.

Clamping rings 20 are preferably semi-circular members and the trailing ends thereof are preferably beveled in order to facilitate movement of loading rings 8" thereover. The leading ends of loading rings 8 and 8 may be undercut to form lips 8a and thereby take the form, as illustrated in FIGURE 6a, in order to provide interengaging ends of the loading rings. Loading rings 8" have longer extensions in order to provide sufiicicnt covering and protection to the insulation of the cable means.

Additionally, cable insulation means 19 may be compressed against loading rings 8" by tapered ends 22 of inner sleeve 13' thereby providing an environmental seal 'at 21 which, with a seal 23 located in the central portion of the connection, provides a complete environmental seal.

The principles outlined in conjunction with the embodiment of FIGURE 9 may 'be'applied to the application of coupling members to similar cable means to provide a disengageable connection instead of a permanent splice. In the. case of providing a disengageable connection, inner sleeve 13 is replaced with sleeves of disengageable members such as illustrated in FIGURE 14 of Serial No. 315,787 and matable center contact members are applied to the center conductors in any suitable manner such as by crimping, soldering, soldering thestranded center conductors and threading thereon the contact members, etc. As can be discerned, there has been disclosed a connection for coaxial cable means and some of the attributes of this connection are: a connection having a profile which is only slightly greater than the outside diameter of the cable, a connection having a minimum impedance change from one cable to the other, a connection wherein the number of parts required are minimized by abutting the dielectrics and center conductors of the cable ends and a connection having improved tensile strength and torque resistance.

It will, therefore, be appreciated that the aforementioned and other desirable objects have been achieved; however, it should be emphasized that the particular embodiments of the invention, which are shown and described herein, are intended as merely illustrative and not at restrictive of the invention.

What is claimed is:

1. A connection assembly for splicing coaxial cable means having center conductor means and rigid outer conductor means separated by dielectric means, said connection assembly comprising center conductor means connectable to said center conductor means for electrically interconnecting said center conductor means, sleeve means disposable between said outer conductor means and said dielectric means for interconnecting said outer conductor means and for bridging thereacross with ends of the center conductor means and dielectric means being disposed adjacent each other inside said sleeve means and ends of said outer conductor means being disposed adjacent each other outside said sleeve means, and loading-ring means for interfacial engagement with said outer conductor means by being forcefully moved along said outer conductor means to a position of rest with first portions of said loading-ring means over said sleeve means to apply radial pressure on said outer conductor means thereby forcing said outer conductor means into tight engagement with said sleeve means and second portions of said loading-ring means extendable along sections of said outer conductor means adjacent said sleeve means.

2. A connection assembly according to claim 1 wherein sealing means is disposed at the juncture of said loading-ring means.

3. A connection assembly according to claim 1 wherein said center contact means is disposed within said center conductor means.

4. A connection assembly according 0t claim 1 wherein said center contact means engages the exterior surface of said center conductor means.

5. A connection assembly according to claim 1 wherein said center contact means includes peripheral ring means to allow equal portions of said center contact means to be connected to said center conductor means.

6. A connection assembly according to claim 1 wherein the leading edges of said loading-ring means includes lip means which interengage when said lip means are moved into engagement.

7. A connection assembly for splicing coaxial cable means having center conductor means, rigid outer conductor means provided with flared ends and dielectric means therebetween comprising center connector means for interconnecting said center conductor means, sleeve means for disposition in the flared ends of said outer conductor means to interconnect said outer conductor means, and loading-ring means movable along said cable means to snugly engage and overlie the flared ends of said cable means in interfacial engagement therewith to apply radial pressure to the flared ends and sleeve means against said dielectric means.

8. A connection assembly for splicing coaxial cable means having center and outer conductor means, dielectric means between said conductor means and insulation means surrounding said outer conductor means, said connection assembly comprising center contact means for interconnecting said ceter conductor means, sleeve means for disposition between said outer conductor means and said dielectric means to bridge the cable means, clampingring means for engagement on said outer conductor means, and loading-ring means movable along said cable means to overlie said clamping-ring means and a portion of said insulation means in interfacial engagement therewith to apply radial pressure to said clamping-ring means, outer conductor means and sleeve means against said deelectric means.

9. A connection assembly for splicing coaxial cable means having center and outer conductor means, dielectric means between said conductor means and insulation means surrounding said outer conductor means, said connection assembly comprising center contact means for connection with said center conductor means, sleeve means for disposition between said outer conductor means and said dielectric means to bridge the cable means, clamping-ring means for engagement on said outer conductor means, and loading-ring means movable along said cable means to a position overlying said clamping-ring means and a portion of said insulation means in interfacial engagement therewith to apply radial pressure to said clamping-ring means, outer conductor means and sleeve means against said dielectric means.

10. A connection for splicing a coaxial cable means having inner and outer conductor means spaced apart by dielectric means, the ends of the outer conductor means to be joined having flared sections which are flared outwardly from the dielectric means to a point inwardly from the ends, said connection comprising an inner contact member mounted on said inner conductor means, a sleeve member disposed within said flared sections between said outer conductor means and said dielectric means with said inner contact means and dielectric means being disposed in contact inside said sleeve member and said flared sections being directed toward each other outside said sleeve member, and comically-shaped loading-ring members in interfacial engagement with said outer conductor means and having leading ends disposed adjacent each other and engaging said outer conductor means and said flared sections thereby applying radial pressure onto said flared sections and sleeve member against said dielectric means.

11. A connection according to claim 10 wherein sealing means is located at the abutting ends of the flared sections and leading ends of said loading-ring members.

12. A connection according to claim 10 wherein said inner contact member includes a peripheral ring so that equal portions of the inner contact member engage said center conductor means.

13. A connection for splicing a coaxial cable means having inner and outer conductor means spaced apart by dielectric means and insulation means surrounding said outer conductor means and stripped back from the ends to expose portions of said outer conductor means, said connection comprising an inner contact member engaging said inner conductor means, a sleeve member disposed between said outer conductor means and said dielectric means with said inner contact means and dielectric means being disposed in contact inside said sleeve member and ends of said outer conductor means being directed toward each other outside said sleeve member, clamping-ring members on the exposed portions of said outer conductor means, and comically-shaped loading-ring members having leading edges disposed adjacent each other and engaging said insulation means and clamping-ring members thereby applying constant radial pressure onto said clamping-ring members, outer conductor means and sleeve member against said dielectric means.

References Cited UNITED STATES PATENTS 2,451,868 10/1948 Quackenbush et a1. l7488 2,536,003 12/1950 Dupre 17488 2,546,309 3/1951 Kempf 174-21 3,245,027 4/1966 Ziegler 174-88 X DARRELL L. CLAY, Primary Examiner. 

7. A CONNECTION ASSEMBLY FOR SPLICING COAXIAL CABLE MEANS HAVING CONDUCTOR MEANS, RIGID OUTER CONDUCTOR MEANS PROVIDED WITH FLARED ENDS AND DIELECTRIC MEANS THEREBETWEEN COMPRISING CENTER CONNECTOR MEANS FOR INTERCONNECTING SAID CENTER CONDUCTOR MEANS, SLEEVE MEANS FOR DISPOSITION IN THE FLARED ENDS OF SAID OUTER CONDUCTOR MEANS TO INTERCONNECT SAID OUTER CONDUCTOR MEANS, AND LOADING-RING MEANS MOVABLE ALONG SAID CABLE MEANS TO SNUGLY ENGAGE AND OVERLIE THE FLARED ENDS OF SAID CABLE MEANS IN INTERFACIAL ENGAGEMENT THEREWITH TO APPLY RADIAL PRESSURE TO THE FLARED ENDS AND SLEEVE MEANS AGAINST SAID DIELECTRIC MEANS. 